For example, in order to compress a process gas in various plants, a centrifugal compressor is used. In the centrifugal compressor, the process gas entering a bundle from a suction port is compressed in a flow channel of an impeller by rotating the impeller along with a rotary shaft, and the process gas is ejected to the outside of the bundle from the discharge port.
Meanwhile, a centrifugal compressor bundle is formed by connecting a plurality of disk-shaped members (diaphragms) such as an intake casing, a discharge casing, and an impeller housing disclosed in PTL 1 in a direction of a rotary shaft. Each diaphragm is divided into two portions on the horizontal plane in a vertical direction.